WAKEFIELD, N.H. — Police in New Hampshire say four on-duty Secret Service agents have been involved in a head-on collision that killed the driver of the other car.

The accident happened at about 7 p.m. Tuesday in Wakefield, near the Maine state line.

Police said early Wednesday that the agents were passengers in a Ford Taurus heading south on Route 16. A northbound Mercury Sable with three people crossed over a double yellow solid line and collided head-on with the Taurus.

The Sable driver, 45-year-old Bruce Danforth, died. A Secret Service spokeswoman said the agents suffered serious but non-life-threatening injuries. They and Danforth’s two passengers were taken to hospitals.

Police are investigating.

It wasn’t immediately known in what capacity the agents were working, but Democratic presidential candidate Hillary Clinton was campaigning in a town hall meeting Tuesday night in Berlin, north of Wakefield.